Boaz Island, formerly known as Gate's Island or Yates Island, is one of the six main islands of Bermuda. It is part of a chain of islands in the west of the country that make up Sandys Parish, lying between the larger Ireland Island and Watford Island, with which it has been joined by a man-made isthmus. South of Watford Island is Somerset Island. Boaz and Watford are connected to Somerset by Watford Bridge, and to Ireland by Gray's Bridge. Watford's east coast forms part of the edge of the Great Sound. The western end of the channel between Boaz and Watford was blocked by the isthmus, creating a camber that opens to the Great Sound. Boaz and Watford Islands were parts of the Royal Naval base, which included the HM Dockyard on Ireland Island.